Compressor device

ABSTRACT

Provided is a compressor device, including: a casing in which a motor (armature and movable element) is housed; an output shaft, which projects from the casing, and is configured to be reciprocated by drive of the motor; a piston provided to a projecting end of the output shaft; a cylinder in which the piston is slidably provided to form a compression chamber; and a cylinder head connected to the cylinder. A tubular shield corresponding to a shielding portion configured to cover the cylinder in such a manner as to be separate from the cylinder in a radial direction of the cylinder is provided on an outer periphery side of the cylinder. The cylinder, the cylinder head, and the tubular shield are coupled to be integrated.

TECHNICAL FIELD

The present invention relates to a compressor device to be mounted in a vehicle such as a four-wheeled automobile so as to, for example, generate a compressed air.

BACKGROUND ART

As a compressor device to be mounted in a vehicle such as a four-wheeled automobile, there is known a compressor device using a linear motor as a driving source (see, for example, Patent Literature 1). This kind of linear motor type compressor can drive a piston reciprocating inside a cylinder with a linear thrust, and hence is a compression machine that does not need a link like a crank mechanism. Thus, the linear motor type compressor has a smaller mechanical loss and a smaller number of vibratory sources of vibration noise than a rotary-to-linear mechanism compression machine, and hence has higher efficiency and superiority in low noise.

CITATION LIST Patent Literature

PTL 1 JP 2018-62917 A

SUMMARY OF INVENTION Technical Problem

In the linear motor type compressor as described in Patent Literature 1, air compression and discharge noise is generated by the piston reciprocating inside the cylinder. Thus, the inventors of the present invention have considered achievement of sound insulation by covering the cylinder, which is a noise generation source. However, the cylinder is also a heat generation source. When an outer side of the cylinder is covered with, for example, a sound insulation cover, heat radiated from the cylinder to an outside air stays inside the sound insulation cover. Accordingly, a temperature of a compressed air may disadvantageously rise.

Solution To Problem

An object of the present invention is to provide a compressor device that enables improvement of a sound insulation property for compression and discharge noise and suppression of temperature rise of a compressed air.

According to one embodiment of the present invention, there is provided a compressor device, including: a casing in which a motor is housed; an output shaft, which projects from the casing, and is configured to be reciprocated by drive of the motor; a piston provided to a projecting end of the output shaft; a cylinder in which the piston is slidably provided to form a compression chamber; and a cylinder head connected to the cylinder, wherein a shielding portion configured to cover the cylinder in such a manner as to be separate from the cylinder in a radial direction of the cylinder is provided on an outer periphery side of the cylinder, and wherein the cylinder, the cylinder head, and the shielding portion are coupled to be integrated.

According to one embodiment of the present invention, the sound insulation property for compression and discharge noise can be improved, and the temperature rise of the compressed air can be suppressed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view for illustrating a linear motor compression machine, which is a linear motor type compressor device according to an embodiment.

FIG. 2 is a longitudinal sectional view of the linear motor compression machine illustrated in FIG. 1.

FIG. 3 is a perspective view for illustrating a tubular shield, which is integrated with a cylinder, as a single body when viewed in a direction indicated by arrows III of FIG. 2.

FIG. 4 is a perspective view for illustrating, in a simplified manner, a state in which a cylinder head is coupled to the tubular shield integrated with the cylinder.

FIG. 5 is a sectional view of the tubular shield integrated with the cylinder, which is taken along a line V-V of FIG. 3 and viewed in a direction of arrows.

FIG. 6 is a pneumatic circuit diagram for illustrating an air suspension system to which the linear motor compression machine is applied.

FIG. 7 is a view for illustrating a tubular shield of a modification example, which is integrated with a cylinder, as a single body.

DESCRIPTION OF EMBODIMENT

A compressor device according to an embodiment of the present invention is now described in detail with reference to FIG. 1 to FIG. 6 of the accompanying drawings, taking an example in which the compressor device is formed as a linear motor type compressor device.

In FIG. 1, a linear motor type compressor device 1 (hereinafter referred to as “linear motor compression machine 1”) includes, for example, a linear motor 2, a compression unit 10, a tubular shield 15, a cylinder head 20, and an air dryer 23. The compression unit 10 includes a cylinder 11 and a piston 12. When a current is caused to flow through coils of armatures 4 (not shown), the linear motor 2 reciprocates a movable element 5 in a longitudinal direction (axial direction) of the linear motor 2 so that the piston 12 of the compression unit 10 is driven in the longitudinal direction to reciprocate.

The linear motor 2 is provided as a driving source for the linear motor compression machine 1 (compression unit 10). The linear motor 2 is mounted on, for example, a floor panel (not shown) of a vehicle body. The linear motor 2 includes a casing 3, the armatures 4, the movable element 5, a support member 6, and a spring 7. The casing 3 forms an outer shell of the linear motor 2. The armatures 4, the movable element 5, the support member 6, and the spring 7 are disposed inside the casing 3. The casing 3 of the linear motor 2 is formed as, as illustrated in FIG. 2, a hollow container having a bottomed cylindrical shape, which is open on one side and is closed on another side in an axial direction of the casing 3. The armatures 4, the movable element 5, the support member 6, and the spring 7, which form the motor 1, are housed in the casing 3.

The energization of the armatures 4 generates magnetic attracting force and repelling force between the armatures 4 and the movable element 5. As a result, the movable element 5 having a flat plate-like shape is driven in such a manner as to repeat reciprocation in the longitudinal direction (axial direction) between a pair of the armatures 4 inside the casing 3. The spring 7 is formed of, for example, a compression coil spring. The spring 7 constantly urges the movable element 5 toward another side (closed end side) of the casing 3 in the axial direction. When the movable element 5 is reciprocated in the axial direction, the spring 7 is elastically flexurally deformed so as to be extended and compressed in the axial direction along with the reciprocation of the movable element 5.

The casing 3 of the linear motor 2 houses the motor including, for example, the armatures 4 and the movable element 5 therein. Among the components of the motor, the movable element 5 has an output shaft 5A. The output shaft 5A projects from the casing 3 into the cylinder 11 described later, and is reciprocated by drive of the motor. The piston 12 described later is provided to a projecting end of the output shaft 5A.

An inverter case 8 having a tubular shape is provided on the another side (closed end side) of the casing 3 in the axial direction. A control inverter 9 is provided inside the inverter case 8, as indicated by an alternate long and two short dashes line. The control inverter 9 includes, for example, a power transistor configured to generate a high voltage for the energization of the armatures 4.

The compression unit 10 of the linear motor compression machine 1 is provided in a state of being sandwiched between the linear motor 2 and the air dryer 23. The compression unit 10 includes, for example, the cylinder 11, the piston 12, a discharge port 13, a discharge valve 14, the tubular shield 15, and the cylinder head 20. When the piston 12 is driven so as to reciprocate in the axial direction together with the movable element 5 of the linear motor 2, the compression unit 10 compresses air in the cylinder 11 to generate a compressed air (specifically, a working gas).

The cylinder 11 is formed in a cylindrical shape with a metal material, for example, aluminum. The piston 12 is reciprocatably (slidably) inserted into the cylinder 11. The piston 12 is coupled to the movable element 5 of the linear motor 2, specifically, the projecting end of the output shaft 5A. As a result, the piston 12 is provided in such a manner as to slide and be displaced in an axial line direction, specifically, the axial direction being the longitudinal direction of the linear motor 2 (casing 3), and is reciprocated inside the cylinder 11 in association with the reciprocation of the movable element 5. In other words, the piston 12 is arranged on an axial line extending in the same direction as a moving direction of the movable element 5 of the linear motor 2.

In this embodiment, the cylinder 11 has the discharge port 13 and the discharge valve 14. The discharge valve 14 is configured to cover the discharge port 13 in such a manner as to be able to open and close the discharge port 13. In a suction stroke performed in the compression unit 10, the discharge valve 14 closes the discharge port 13 to cut off the cylinder 11 from the air dryer 23 side. In a compression stoke, the discharge valve 14 opens the discharge port 13 to bring an inside of the cylinder 11 into communication with the air dryer 23. Further, the tubular shield 15 is provided on an outer periphery side of the cylinder 11. The tubular shield 15 corresponds to a shielding portion that is configured to cover the cylinder 11 in such a manner as to be separate from the cylinder 11 to a radially outer side.

As illustrated in FIG. 3 to FIG. 5, the tubular shield 15 includes a tubular portion 15A, a partition wall portion 15B, and a plurality of ribs 15C, 15D, 15E, and 15F. The tubular portion 15A having a substantially rectangular shape extends in the axial direction over the entire length of the cylinder 11, and surrounds the cylinder 11 on a radially outer side thereof. The partition wall portion 15B is formed integrally with the tubular portion 15A in such a manner as to close one side of the tubular portion 15A in the axial direction except for the cylinder 11. The plurality of ribs 15C, 15D, 15E, and 15F are arranged in a cross-like shape so as to integrally couple the cylinder 11 and the tubular portion 15A.

The ribs 15C, 15D, 15E, and 15F extend radially (crosswise) from an outer periphery of the cylinder 11 toward an inner wall of the tubular portion 15A to integrally couple the cylinder 11 and the tubular portion 15A. In other words, the cylinder 11 and the shielding portion, specifically, the tubular portion 15A of the tubular shield 15 are connected to each other with the plurality of ribs 15C, 15D, 15E, and 15F. The tubular shield 15 is made of the same material (for example, a metal material such as aluminum) as that of the cylinder 11, and is integrally formed by casting such as aluminum die casting. A screw hole 16 extending in the axial direction is formed in each of the ribs 15C, 15D, 15E, and 15F of the tubular shield 15. A connecting bolt 22 (see FIG. 2) described later is threadably fitted into each of the screw holes 16 so as to couple the cylinder head 20 to the tubular shield 15, specifically, integrate the cylinder head 20 with the tubular shield 15.

In this case, for example, four valve housing spaces 17 in total are defined through partition with the ribs 15C, 15D, 15E, and 15F between the tubular portion 15A of the tubular shield 15 and the cylinder 11. An intake electromagnetic valve 38, a return electromagnetic valve 40, a supply/exhaust switching valve 41, and an exhaust electromagnetic valve 44, which are described later, are individually housed in the valve housing spaces 17. As an example, in FIG. 7 corresponding to a modification example, the intake electromagnetic valve 38 is arranged in the valve housing space 17 located between the ribs 15C and 15D, and the return electromagnetic valve 40 is arranged in the valve housing space 17 located between the ribs 15D and 15E. Further, the supply/exhaust switching valve 41 is arranged in the valve housing space 17 located between the ribs 15E and 15F, and the exhaust electromagnetic valve 44 is arranged in the valve housing space 17 located between the ribs 15C and 15F. Arrangement of the valves 38, 40, 41, and 44 to the valve housing spaces 17 is suitably selected and determined in a stage of designing.

Valve fitting holes 18A and 18B are formed in the partition wall portion 15B of the tubular shield 15. The valve fitting hole 18A is formed of a stepped hole, and is formed in such a manner as to be in communication with the valve housing space 17 defined between the ribs 15C and 15D. The valve fitting hole 18B different from the valve fitting hole 18A is formed of a stepped hole, and is formed in such a manner as to be in communication with the valve housing space 17 defined between the ribs 15D and 15E. An end portion of the intake electromagnetic valve 38, the return electromagnetic valve 40, the supply/exhaust switching valve 41, or the exhaust electromagnetic valve 44, which are described later, is fitted into each of the valve fitting holes 18A and 18B to be positioned thereby.

Further, four bolt insertion holes 19 in total are formed in the valve housing spaces 17 in such a manner as to be located in corners of the tubular portion 15A. Long bolts (not shown) configured to integrally couple and fix the casing 3 of the linear motor 2, the cylinder head 20, and the cylindrical shield 15 are inserted into the bolt insertion holes 19 under a state in which the tubular shield 15 (specifically, the cylinder 11) is sandwiched between the casing 3 of the linear motor 2 and the cylinder head 20. Bolt insertion holes into which the long bolts are to be inserted are similarly formed in the cylinder head 20 illustrated in a simplified manner in FIG. 4. In FIG. 4, however, illustration of the bolt insertion holes is omitted.

The cylinder head 20 is disposed on one end side of the tubular shield 15 (specifically, the cylinder 11) so as to abut against and be coupled to one end (specifically, the discharge port 13) side of the cylinder 11. As illustrated in a simplified manner in FIG. 4, the cylinder head 20 includes a head cylinder 20A, an outer tubular portion 20B, and a plurality of ribs 20C, 20D, 20E, and 20F. The head cylinder 20A is located on a center side. The outer tubular portion 20B is located on an outer periphery side, and has a substantially rectangular shape. The plurality of ribs 20C, 20D, 20E, and 20F are formed to have a cross-like shape to integrally couple the head cylinder 20A and the outer tubular portion 20B.

The head cylinder 20A of the cylinder head 20 is disposed to abut against the one end (specifically, the discharge port 13) side of the cylinder 11 in such a manner as to be coaxial with the cylinder 11. The outer tubular portion 20B of the cylinder head 20 is formed as a tubular body having a substantially rectangular shape, which surrounds the head cylinder 20A on a radially outer side thereof, as in the case of the tubular portion 15A of the tubular shield 15. The tubular portion 15A and the outer tubular portion 20B are caused to abut against each other in such a manner as to be aligned with each other. Further, the ribs 20C, 20D, 20E, and 20F of the cylinder head 20 are also caused to abut against the ribs 15C, 15D, 15E, and 15F of the tubular shield 15 in such a manner as to be aligned therewith.

For example, four valve housing spaces 21 in total, which are separated by the ribs 20C, 20D, 20E, and 20F, are defined between the head cylinder 20A and the outer tubular portion 20B of the cylinder head 20. The valve housing spaces 21 are in communication with the valve housing spaces 17 of the tubular shield 15, respectively. The intake electromagnetic valve 38, the return electromagnetic valve 40, the supply/exhaust switching valve 41, and the exhaust electromagnetic valve 44, which are described later, are individually housed in the valve housing spaces 17 and 21, respectively.

As illustrated in FIG. 2, the plurality of connecting bolts 22 are threadably fitted into the screw holes 16 of the tubular shield 15, respectively. As a result, the cylinder head 20 is fixed so as to be integrated with the tubular shield 15. In the cylinder head 20 illustrated in FIG. 4, illustration of the above-mentioned connecting bolts 22, bolt holes, and other portions is omitted. The illustration of the above-mentioned members and portions is omitted so as to clearly illustrate, for example, shapes of the ribs 20C, 20D, 20E, and 20F formed between the head cylinder 20A and the outer tubular portion 20B of the cylinder head 20.

The air dryer 23 is provided and fixed to one end of the cylinder head 20. The air dryer 23 is located on one side of the cylinder head 20 in the axial direction, and is provided on a side opposite to the linear motor 2 through the cylinder head 20 and the tubular shield 15 (cylinder 11) therebetween. An inflow port 25A side, which is described later, of the air dryer 23 is connected to the head cylinder 20A of the cylinder head 20. Desiccant beads 26 are loaded in an inner tube 25.

In this case, the air dryer 23 is arranged in series to the piston 12 so that an axial line direction thereof extends along an axial line direction of the piston 12. Specifically, an axial line of the air dryer 23 and an axial line of the cylinder 11 (piston 12) extend in the axial direction substantially in alignment with each other. In other words, the air dryer 23 is arranged on an axial line extending in the moving direction of the movable element 5 of the linear motor 2 and the piston 12. With this arrangement, a radial dimension of the linear motor compression machine 1 can be reduced to enhance vehicle mountability of the compression machine.

The air dryer 23 includes an outer tube 24, the inner tube 25, a large number of desiccant beads 26, and an annular passage 27. The outer tube 24 forms an outer shell of the air dryer 23. The inner tube 25 is arranged inside the outer tube 24. The large number of desiccant beads 26 are stored in the inner tube 25 in a state of being loaded in the inner tube 25. The annular passage 27 is defined between the outer tube 24 and the inner tube 25. The annular passage 27 of the air dryer 23 forms a part of a supply/exhaust pipeline 33 (see FIG. 6), which is described later. The annular passage 27 is connected to a tank pipeline 39 at a position of a connection point 33B, and is connected to an air conduit 34 through intermediation of the supply/exhaust switching valve 41.

When a compressed air flowing into the air dryer 23 from the inflow port 25A of the inner tube 25 is brought into contact with the desiccant beads 26 inside the inner tube 25, the desiccant beads 26 absorb moisture contained in the compressed air to dry the air. The dried compressed air flows from an outflow port 25B of the inner tube 25 via the annular passage 27 defined between the outer tube 24 and the inner tube 25 toward the return electromagnetic valve 40 or the supply/exhaust switching valve 41, which are described later.

The inner tube 25 is formed in a cylindrical shape as a hollow container made of a metal material, for example, aluminum. The large number of desiccant beads 26 are loaded in the inner tube 25 to be located between filters 28A and 28B that are separate apart from each other in a fore-and-aft direction. The filters 28A and 28B are configured to prevent part of the desiccant beads 26 from flowing out to an outside. Further, a spring 29 configured to constantly urge the filter 28B in a direction away from a bottom portion 24A is provided between the filter 28B and the bottom portion 24A of the outer tube 24 so as to prevent rattling movement and vibration of the desiccant beads 26 between the filters 28A and 28B.

Next, with reference to FIG. 6, description is made of an example case in which the linear motor compression machine 1 according to this embodiment is applied to an air suspension system for a vehicle as represented by a four-wheeled automobile. The air suspension system includes, for example, the linear motor compression machine 1, a plurality of air suspensions 31, the air conduit 34, and a plurality of air supply/exhaust valves 35.

Four air suspensions 31 in total are provided on a front left wheel (FL) side, a front right wheel (FR) side, a rear left wheel (RL) side, and a rear right wheel (RR) side of a vehicle between each axle of the vehicle and a vehicle body (all not shown). When the compressed air is supplied to or exhausted from air chambers 31C described later, the air suspensions 31 perform vehicle height adjustment in accordance with expansion and contraction of the air chambers 31C.

Each of the air suspensions 31 includes a cylinder 31A, a piston rod 31B, and the air chamber 31C. The cylinder 31A is mounted to, for example, the axle side of the vehicle. The piston rod 31B projects from the cylinder 31A in such a manner as to be able to advance and retreat in the axial direction, and has a projecting end to be mounted to the vehicle body. The air chamber 31C is provided expandably and contractably between the projecting end of the piston rod 31B and the cylinder 31A to work as an air spring. When the compressed air is supplied to and exhausted from the air chamber 31C through a branch pipe 34A described later, the air chamber 31C of each of the air suspensions 31 is expanded and contracted in the axial direction. At this time, in each of the air suspensions 31, the piston rod 31B advances from and retreats toward the cylinder 31A in the axial direction to adjust a height of the vehicle (vehicle height) in accordance with a supply/exhaust amount of the compressed air.

In this case, the air suspensions 31 form a vehicle height adjustment device configured to vertically movably support the vehicle body. Specifically, when the compressed air from the linear motor compression machine 1 is supplied or exhausted, the air suspensions 31 is vertically expanded or contracted in accordance with a supply/exhaust amount (compressed air amount) given at that moment to perform the vehicle height adjustment for the vehicle. The air suspensions 31 are connected to the compression unit 10 of the linear motor compression machine 1 through intermediation of the air conduit 34.

An intake pipeline 32 is connected to an intake side of the linear motor compression machine 1 (compression unit 10), and the supply/exhaust pipeline 33 is connected to the discharge valve 14 side of the compression unit 10. The supply/exhaust pipeline 33 includes, for example, the annular passage 27 of the air dryer 23, which is illustrated in FIG. 2. A distal end of the supply/exhaust pipeline 33 is connected to the air conduit 34 through intermediation of the supply/exhaust switching valve 41 described later. The air dryer 23 is provided in the middle of the supply/exhaust pipeline 33.

The intake pipeline 32 forms an intake passage of the linear motor compression machine 1. A tank-side inlet pipeline 37 and a reflux pipeline 42, which are described later, are connected at a position of a connection point 32C. As a matter of course, the tank-side inlet pipeline 37 and the reflux pipeline 42 may be connected to the intake pipeline 32 at different points in the vicinity of the connection point 32C.

The intake pipeline 32 has an intake port 32A on one end side. The intake port 32A is open to an outside of the linear motor compression machine 1. A filter (not shown) configured to remove, for example, dust in the air is provided to the intake port 32A. Another end of the intake pipeline 32 is connected to the intake side of the compression unit 10. An intake valve 32B formed of a check valve is provided in the middle of the intake pipeline 32. In the linear motor compression machine 1 illustrated in FIG. 2, however, illustration of the components such as the intake pipeline 32 and the intake valve 32B is omitted.

The supply/exhaust pipeline 33 forms a supply/exhaust passage configured to supply and exhaust the compressed air generated in the compression unit 10 of the linear motor compression machine 1 to and from the air chambers 31C of the air suspensions 31. When the vehicle height is reduced, the compressed air supplied to the air chambers 31C of the air suspensions 31 is exhausted from the air chambers 31C via the supply/exhaust pipeline 33, for example, to flow back through the air dryer 23 or escape into a tank 36 described later.

Further, an exhaust pipeline 43 branches from the supply/exhaust pipeline 33 at a connection point 33A located between the discharge valve 14 and the air dryer 23 of the linear motor compression machine 1. The tank pipeline 39 branches from the supply/exhaust pipeline 33 at the connection point 33B located between the air dryer 23 and the supply/exhaust switching valve 41. In other words, the air dryer 23 is provided to the supply/exhaust pipeline 33 at a position between the connection points 33A and 33B. A slow return valve (not shown) may be provided to the supply/exhaust pipeline 33 at a position between the air dryer 23 and the connection point 33B.

The air dryer 23 forms an air drying unit provided in the middle of the supply/exhaust pipeline 33. The air dryer 23 stores the desiccant beads 26 (see FIG. 2), for example, silica gel, and is disposed between the discharge valve 14 and the supply/exhaust switching valve 41 of the linear motor compression machine 1. When the high-pressure compressed air generated in the compression unit 10 flows through the supply/exhaust pipeline 33 in a forward direction toward the air suspensions 31, moisture is adsorbed by bringing the compressed air into contact with the desiccant beads 26 stored therein. The air dryer 23 supplies the dried compressed air toward the air chambers 31C of the air suspensions 31.

Meanwhile, when the compressed air, specifically, the exhaust air exhausted from the air chambers 31C of the air suspensions 31 flows through the air dryer 23 (supply/exhaust pipeline 33) in a backward direction, the dried air flows back through the air dryer 23. Thus, moisture contained in the desiccant beads 26 in the air dryer 23 is desorbed with the dried air. As a result, the desiccant beads 26 in the air dryer 23 are regenerated to a moisture adsorbable state again.

The air chambers 31C of the air suspensions 31 are connected to the supply/exhaust pipeline 33 of the linear motor compression machine 1 through intermediation of the supply/exhaust switching valve 41 and the air conduit 34. In this case, a plurality of (for example, four) branch pipes 34A branching from the air conduit 34 are provided. Distal ends of the branch pipes 34A are removably connected to the air chambers 31C of the air suspensions 31, respectively.

The air supply/exhaust valve 35 for the compressed air is provided in the middle of each of the branch pipes 34A so as to control the supply and exhaust of the compressed air to and from the air chamber 31C of the air suspension 31. Each of the air supply/exhaust valves 35 is formed of, for example, a 2-port 2-position electromagnetic switching valve (solenoid valve). Each of the air supply/exhaust valves 35 is normally placed in a valve closed position (a). When excited by a control signal output from a controller (not shown), the air supply/exhaust valve 35 is switched from the valve closed position (a) to a valve open position (b).

Each of the air supply/exhaust valves 35 may be connected and provided between the air chamber 31C of the air suspension 31 and the branch pipe 34A. Further, each of the air supply/exhaust valves 35 has a function as a relief valve (safety valve). Thus, when pressure in the air chamber 31C exceeds a relief set pressure, the air supply/exhaust valve 35 is temporarily switched from the valve closed position (a) to the valve open position (b) as a relief valve even though the air supply/exhaust valve 35 remains demagnetized. Thus, an overpressure generated at this time is released into the air conduit 34.

The tank 36 that stores the compressed air has a connection pipe 36A formed of, for example, a flexible hose. The connection pipe 36A has one end that is removably connected to the tank 36 and another end that is connected to the tank-side inlet pipeline 37 and the tank pipeline 39, which are described later. The connection pipe 36A of the tank 36 is connected to the intake side of the compression unit 10 through intermediation of the tank-side inlet pipeline 37. The tank-side inlet pipeline 37 has one end that is connected to the tank 36 (connection pipe 36A) and another end that is connected to the intake pipeline 32 at the position of the connection point 32C. Specifically, the intake pipeline 32 is connected to the tank-side inlet pipeline 37 in such a manner that the tank-side inlet pipeline 37 branches from the intake pipeline 32 at the connection point 32C, which is located at a position between the intake side of the compression unit 10 and the intake valve 32B.

The intake electromagnetic valve 38 configured to supply and stop supplying the compressed air in the tank 36 to the intake side of the compression unit 10 is provided to the tank-side inlet pipeline 37. The intake electromagnetic valve 38 is formed of, for example, a 2-port 2-position electromagnetic switching valve (solenoid valve). The intake electromagnetic valve 38 is normally placed in a valve closed position (c). When excited by a control signal from the controller, the intake electromagnetic valve 38 is switched from the valve closed position (c) to a valve open position (d). Further, similarly to the air supply/exhaust valve 35 described above, the intake electromagnetic valve 38 has a function as a relief valve (safety valve).

The intake electromagnetic valve 38 is an on/off electromagnetic valve to be switched between the valve closed position (c) and the valve open position (d). A highly versatile electromagnetic switching valve may be employed as the intake electromagnetic valve 38. Thus, an expensive valve, for example, a three-way electromagnetic valve is not needed. Similarly to the intake electromagnetic valve 38, a highly versatile electromagnetic switching valve may be employed for each of the return electromagnetic valve 40 and the exhaust electromagnetic valve 44, which are described later.

The connection pipe 36A of the tank 36 is connected to the discharge valve 14 side of the compression unit 10 through intermediation of the tank pipeline 39. The tank pipeline 39 has one end that is connected to the tank 36 (connection pipe 36A) and another end that is connected to the supply/exhaust pipeline 33 at the position of the connection point 33B in such a manner as to branch therefrom. Specifically, the supply/exhaust pipeline 33 is connected to the tank pipeline 39 in such a manner that the tank pipeline 39 branches from the supply/exhaust pipeline 33 at the connection point 33B, which is located between the air dryer 23 and the supply/exhaust switching valve 41.

The return electromagnetic valve 40 is provided to the tank pipeline 39. The return electromagnetic valve 40 serves as a return valve configured to supply the compressed air in the tank 36 so as to return the compressed air into the supply/exhaust pipeline 33 and stop the supply of the compressed air. The return electromagnetic valve 40 is formed of, for example, a 2-port 2-position electromagnetic switching valve (solenoid valve). The return electromagnetic valve 40 is normally placed in a valve closed position (e). When excited by a control signal output from the controller, the return electromagnetic valve 40 is switched from the valve closed position (e) to a valve open position (f). When the return electromagnetic valve 40 is open, for example, pressure accumulation can be performed to return the compressed air in the air suspensions 31 to the tank 36 via the tank pipeline 39. Further, similarly to the air supply/exhaust valve 35 described above, the return electromagnetic valve 40 has a function as a relief valve (safety valve).

The supply/exhaust switching valve 41 is configured to selectively connect the air conduit 34 located on the air suspension 31 side to the supply/exhaust pipeline 33 or the reflux pipeline 42. The supply/exhaust switching valve 41 is formed of, for example, a 3-port 2-position electromagnetic directional switching valve. Specifically, the supply/exhaust switching valve 41 is selectively switched between a supply/exhaust position (g) and a reflux position (h). When the supply/exhaust switching valve 41 is in the supply/exhaust position (g), the compressed air generated in the linear motor compression machine 1 is supplied to the air chambers 31C of the air suspensions 31, or the compressed air in the air chambers 31C is exhausted via the supply/exhaust pipeline 33. When the supply/exhaust switching valve 41 is in the reflux position (h), the compressed air in the air chambers 31C is caused to reflux to the intake side of the compression unit 10 via the reflux pipeline 42.

The reflux pipeline 42 is a bypass passage provided in such a manner as to bypass the compression unit 10, the supply/exhaust pipeline 33, and the air dryer 23. One end of the reflux pipeline 42 can be connected to the air conduit 34 located on the air suspension 31 side through intermediation of the supply/exhaust switching valve 41. Another end of the reflux pipeline 42 is connected to the intake pipeline 32 at the position of the connection point 32C. Thus, when the supply/exhaust switching valve 41 is switched to the reflux position (h), the reflux pipeline 42 allows the compressed air exhausted from the air chambers 31C of the air suspensions 31 to reflux to the intake side of the compression unit 10 in such a manner that the compressed air bypasses the supply/exhaust pipeline 33.

The exhaust pipeline 43 is a passage configured to exhaust the compressed air in the supply/exhaust pipeline 33 to the outside. In the middle of the exhaust pipeline 43, the exhaust electromagnetic valve 44 is provided. One end of the exhaust pipeline 43 is connected to the supply/exhaust pipeline 33 at a position of the connection point 33A. Another end of the exhaust pipeline 43 extends to an outside of the compressor device (linear motor compression machine 1), and has an exhaust port 43A formed at a distal end thereof.

The exhaust electromagnetic valve 44 serving as an exhaust valve is formed of, for example, a 2-port 2-position electromagnetic switching valve (solenoid valve). The exhaust electromagnetic valve 44 is normally placed in a valve closed position (i). When excited by a control signal from the controller, the exhaust electromagnetic valve 44 is switched from the valve closed position (i) to a valve open position (j). When the exhaust electromagnetic valve 44 is open, the compressed air in the tank 36 can be exhausted (released) from the exhaust port 43A via the supply/exhaust pipeline 33, the air drier 23, and the exhaust pipeline 43, or the compressed air in the air suspensions 31 can be exhausted (released) from the exhaust port 43A via the supply/exhaust pipeline 33, the air dryer 23, the exhaust pipeline 43 to the outside. Further, similarly to the air supply/exhaust valve 35 described above, the exhaust electromagnetic valve 44 has a function as a relief valve (safety valve).

Further, a pressure detector 45 is provided to the air conduit 34 at a position, for example, between the branch pipes 34A and the supply/exhaust switching valve 41. When, for example, the return electromagnetic valve 40 is switched from the valve closed position (e) to the valve open position (f) under a state in which all the air supply/exhaust valves 35, the intake electromagnetic valve 38, and the exhaust electromagnetic valve 44 are closed to return the supply/exhaust switching valve 41 to the supply/exhaust position (g), the pressure detector 45 detects a pressure in the tank 36 via the tank pipeline 39. Further, when, for example, at least one of the air supply/exhaust valves 35 is opened under a state in which the intake electromagnetic valve 38, the return electromagnetic valve 40, and the exhaust electromagnetic valve 44 are closed, a pressure in the air chamber 31C of a corresponding one of the air suspensions 31 can be detected by the pressure detector 45.

The intake electromagnetic valve 38, the return electromagnetic valve 40, the supply/exhaust switching valve 41, and the exhaust electromagnetic valve 44 of the linear motor compression machine 1 correspond to solenoid valves configured to control supply and exhaust of the compressed air to and from the air dryer 23. As exemplified in FIG. 2 and FIG. 7, the solenoid valves (the intake electromagnetic valve 38, the return electromagnetic valve 40, the supply/exhaust switching valve 41, and the exhaust electromagnetic valve 44) are located on the radially outer side of the cylinder 11, and are fixed in a sandwiched state between the casing 3 and the cylinder head 20. The solenoid valves (the intake electromagnetic valve 38, the return electromagnetic valve 40, the supply/exhaust switching valve 41, and the exhaust electromagnetic valve 44) are individually housed in the valve housing spaces 17 partitioned by the ribs 15C, 15D, 15E, and 15F between the tubular portion 15A of the tubular shield 15 and the cylinder 11.

Further, the linear motor compression machine 1 includes joints 46 and 47. The joint 46 is configured to connect the supply/exhaust pipeline 33 to the air conduit 34 located outside. The connection pipe 36A of the tank 36 is connected to the joint 47. As illustrated in FIG. 1, the joints 46 and 47 are provided to, for example, the outer tubular portion 20B of the cylinder head 20.

The linear motor compression machine 1 (linear motor type compressor) according to this embodiment has the configuration described above. An operation of the linear motor compression machine 1 is now described.

First, when the coils (not shown) of the armatures 4 of the linear motor 2 are supplied with a current (energized), the movable element 5 receives a thrust in the axial direction. As a result, the whole movable element 5 is driven in the fore-and-aft direction (axial direction) of the vehicle. At this time, the energization of the coils (not shown) of the armatures 4 generates magnetic attracting force and repelling force between the armatures 4 and the movable element 5. As a result, the movable elements 5 having a flat plate-like shape is driven to repeat reciprocation in the length direction (axial direction) between the pair of armatures 4 inside the casing 3.

A thrust generated along with the reciprocation of the movable element 5 is transmitted to the piston 12 inside the compression unit 10 (cylinder 11). The piston 12 repeats the reciprocation in the axial direction inside the cylinder 11 to perform a compression operation. Specifically, while the piston 12 is performing a suction stroke, the pressure in the cylinder 11 tends to be negative. Along with the negative pressure tendency, the intake valve 32B (see FIG. 6) is opened. As a result, an outside air is sucked from the intake port 32A (see FIG. 6) into the cylinder 11 via the intake pipeline 32.

Meanwhile, while the piston 12 is performing a compression stroke, the pressure in the cylinder 11 is increased by displacement of the piston 12 inside the cylinder 11 under a state in which the intake valve 32B (see FIG. 6) is closed. Then, when the pressure in the cylinder 11 becomes larger than a valve-opening pressure for the discharge valve 14, the discharge valve 14 is opened. As a result, the compressed air generated in the cylinder 11 is discharged toward the air dryer 23 via the cylinder head 20. In the air dryer 23, the compressed air is brought into contact with the desiccant beads 26 to remove moisture through adsorption. The dried compressed air is supplied to the air chambers 31C of the air suspensions 31 via the annular passage 27 (supply/exhaust pipeline 33) of the air dryer 23 and the air conduit 34 (branch pipes 34A).

When the compressed air is supplied to the air suspensions 31 to increase the vehicle height of the vehicle body, each of the air supply/exhaust valves 35 provided in the middle of the branch pipes 34A is switched from the valve closed position (a) to the valve open position (b). Actuation of the compression unit 10 of the linear motor compression machine 1 under the above-mentioned state allows supply of the compressed air generated in the compression unit 10 to the air suspensions 31 on a front wheel side and a rear wheel side via the branch pipes 34A branching from the air conduit 34.

When the vehicle height on the vehicle body side reaches a target height, the air supply/exhaust valves 35 are returned to the valve closed positions (a) to close the branch pipes 34A so as to terminate a vehicle-height increasing operation. As a result, the supply of the compressed air to the air suspensions 31 on the front wheel side and the rear wheel side is stopped. Under this state, the air suspensions 31 are maintained in an expanded state to keep the vehicle height on the vehicle body side at the target height.

Meanwhile, when the vehicle height is to be reduced, each of the air supply/exhaust valves 35 provided in the middle of the branch pipes 34A is switched to the valve open position (b). At the same time, for example, the exhaust electromagnetic valve 44 is switched from the valve closed position (i) to the valve open position (j). As a result, the compressed air in the air suspensions 31 is exhausted into the air dryer 23 via the branch pipes 34A branching from the air conduit 34, the supply/exhaust switching valve 41, and the supply/exhaust pipeline 33. At this time, the compressed air flows back through the air dryer 23 to take away moisture adsorbed by the desiccant beads 26 to thereby regenerate the desiccant beads 26.

After having flowed through the air dryer 23, the compressed air is exhausted (released) from the supply/exhaust pipeline 33 through the exhaust pipeline 43, the exhaust electromagnetic valve 44, and the exhaust port 43A to the outside. As a result, the compressed air is exhausted from the air suspensions 31 to contract the air suspensions 31 to thereby enable the vehicle height to be reduced.

Further, when control for reducing the vehicle height is performed, the compressed air may also be exhausted from the air chambers 31C of the air suspensions 31 toward the tank 36. In this case, for the exhaust from the air suspensions 31, each of the air supply/exhaust valves 35 for the air suspensions 31 is switched from the valve closed position (a) to the valve open position (b), and the supply/exhaust switching valve 41 is switched from the supply/exhaust position (g) to the reflux position (h). After that, the compression unit 10 is driven by the linear motor 2 to perform control for switching the return electromagnetic valve 40 from the valve closed position (e) to the valve open position (f).

Through the control described above, the compressed air from the air chambers 31C of the air suspensions 31 is sucked into the compression unit 10 from the intake side thereof via the supply/exhaust switching valve 41 and the reflux pipeline 42, and is supplied (exhausted) from the discharge valve 14 of the compression unit 10 via the air dryer 23, the supply/exhaust pipeline 33, the tank pipeline 39, and the return electromagnetic valve 40 to be allowed to escape into the tank 36. Thus, the vehicle height can be reduced under a state in which the compressed air for the air suspensions 31 is stored in the tank 36. The compressed air in the air suspension system, specifically, the compressed air, which has been compressed in the compression unit 10 and has been dried in the air dryer 23, is not wastefully released to the outside, but can be effectively used for next vehicle height adjustment.

Next, when control for increasing the vehicle height is to be performed under the above-mentioned state, the compressed air in the tank 36 can be supplied to the air chambers 31C of the air suspensions 31 via the compression unit 10. In this case, the intake electromagnetic valve 38 is switched from the valve closed position (c) to the valve open position (d) to bring the tank 36 into communication with the intake pipeline 32. The return electromagnetic valve 40 is returned to the valve closed position (e), and the tank 36 is cut off from the tank pipeline 39.

After that, the compression unit 10 is driven by the linear motor 2 to switch the air supply/exhaust valves 35 for the air suspensions 31 to the valve open positions (b). As a result, the compressed air in the tank 36 is sucked from the intake side along with the actuation of the compression unit 10. The compressed air is supplied from the discharge valve 14 to the air chambers 31C of the air suspensions 31 via the air dryer 23 and the supply/exhaust switching valve 41 to enable the vehicle height to be driven in an increasing direction. As described above, when the vehicle height is increased, the air compressed in the compression unit 10 is dried while passing through the air dryer 23, and the compressed air in a dried state is supplied to the air chambers 31C of the air suspensions 31.

In the linear motor type compressor (linear motor compression machine 1), air compression and discharge noise is generated by the piston 12 reciprocating inside the cylinder 11, and is required to be reduced. Thus, the inventors of the present invention have considered achievement of sound insulation by covering the cylinder 11, which is a noise generation source, with, for example, a cover. However, the cylinder 11 is also a heat generation source. Thus, when an outer side of the cylinder 11 is merely covered with, for example, a sound insulation cover, heat radiated from the cylinder 11 to the outside air may stay inside the sound insulation cover to increase a temperature of the compressed air.

Thus, the linear motor compression machine 1 according to this embodiment includes the casing 3, the output shaft 5A, the piston 12, the cylinder 11, and the cylinder head 20. The motor including the armatures 4 and the movable element 5 is housed in the casing 3. The output shaft 5A projects from the casing 3, and is reciprocated by drive of the motor. The piston 12 is provided to the projecting end of the output shaft 5A. The piston 12 is slidably provided in the cylinder 11 to form a compression chamber. The cylinder head 20 is connected to the cylinder 11. The tubular shield 15 corresponding to the shielding portion configured to cover the cylinder 11 in such a manner as to be separate from the cylinder 11 in a radial direction of the cylinder 11 is provided on the outer periphery side of the cylinder 11. The cylinder 11, the cylinder head 20, and the tubular shield 15 are coupled to be integrated.

With the configuration described above, the tubular shield 15 corresponding to the shielding portion can cover the cylinder 11, which is a compression and discharge noise generation source, on the radially outer side. Thus, a sound insulation effect is achieved. Further, heat generated by, for example, compression heat given when the piston 12 slides inside the cylinder 11 of the compression unit 10 can be transferred to the casing 3 for the motor on one side of the cylinder 11 and the tubular shield 15. The heat is transferred to the cylinder head 20 on another side of the cylinder 11 and the tubular shield 15. In this manner, an increased heat radiation area can be secured.

Further, a surface area of the tubular shield 15 corresponding to the shielding portion is set larger than a surface area of the cylinder 11. Thus, a heat radiation area can be secured. In other words, heat can easily be transferred. Accordingly, a temperature rise of the cylinder 11 can be suppressed. Further, a surface area of the cylinder head 20 is set larger than the surface area of the cylinder 11. Thus, a heat radiation area can be secured. In other words, heat can easily be transferred. Accordingly, the temperature rise of the cylinder 11 can be suppressed. The heat of the cylinder 11 is transferred through the tubular shield 15 corresponding to the shielding portion and the cylinder head 20. Thus, even when the surface area of the cylinder head 20 is smaller than the surface area of the cylinder 11, the heat radiation area is only required to be secured as a whole.

In particular, the tubular portion 15A, which is located on the outer periphery side in the tubular shield 15, is connected to the cylinder 11 located on the inner side thereof through the plurality of ribs 15C, 15D, 15E, and 15F. Thus, a heat capacity of the cylinder 11 can be increased by the tubular shield 15 located on the outer side to suppress the temperature rise of the cylinder 11. In addition, the tubular shield 15 can be molded integrally with the cylinder 11 through, for example, casting such as aluminum die casting, and hence the number of components can be reduced. Accordingly, manufacture cost of the linear motor compression machine 1 can be reduced.

Further, the cylinder 11 and the tubular shield 15 are formed to have an integrated structure with the plurality of ribs 15C, 15D, 15E, and 15F. Thus, stiffness can be increased to suppress structural vibration of the tubular shield 15 serving as a sound insulation cover. Thus, an effect of suppressing radiated sound due to the sound insulation cover itself can be achieved. Further, a heat radiation surface of the cylinder 11 can be increased with the tubular shield 15. Thus, an increase in air temperature in the cylinder 11 can be suppressed.

Besides, the linear motor compression machine 1 according to this embodiment includes the air dryer 23, which is connected to the cylinder head 20 and is loaded with the desiccant beads 26, and the solenoid valves, for example, the intake electromagnetic valve 38, the return electromagnetic valve 40, the supply/exhaust switching valve 41, and the exhaust electromagnetic valve 44 illustrated in FIG. 6 and FIG. 7, which are configured to control the supply and the exhaust of the compressed air to and from the air dryer 23. The solenoid valves are located on the radially outer side of the cylinder 11, and are fixed in a sandwiched state between the casing 3 and the cylinder head 20. The tubular portion 15A of the tubular shield 15 is provided on the outer side of the solenoid valves.

With the arrangement described above, the solenoid valves such as the intake electromagnetic valve 38, the return electromagnetic valve 40, the supply/exhaust switching valve 41, and the exhaust electromagnetic valve 44 can be housed between the cylinder 11 and the tubular portion 15A of the tubular shield 15 in a space-saving manner. The solenoid valves can be arranged in the valve housing spaces 17 (21) in a state of being individually assigned and separated from each other. Further, valve opening and closing noise and switching noise generated from the solenoid valves can be cut by the tubular shield 15. Generation of heat from the solenoid valves can also be suppressed by the tubular shield 15.

Thus, according to this embodiment, the tubular shield 15 corresponding to the shielding portion is provided on the outer periphery side of the cylinder 11. The cylinder 11, the cylinder head 20, and the tubular shield 15 are coupled to be integrated. As a result, a sound insulation property for the compression and discharge noise generated by the cylinder 11 can be enhanced, and the temperature rise of the compressed air in the cylinder 11 can be suppressed.

FIG. 7 is a view for illustrating the tubular shield 15 integrated with the cylinder as a single body, which is taken along a line III-III and viewed in a direction indicated by arrows of FIG. 2. FIG. 7 is a view for illustrating a modification example of this embodiment. In FIG. 7, the tubular shield 15 of this modification example has opening portions 100. The opening portions 100 are formed in regions of the tubular portion 15A of the tubular shield 15, which are opposed to the solenoid valves, for example, the intake electromagnetic valve 38 and the return electromagnetic valve 40, respectively. With the opening portions, heat generated from the solenoid valves can be brought into direct contact with an atmosphere to promote the heat radiation.

In the embodiment, description has been made of the example case in which the linear motor type compressor (linear motor compression machine 1) including the compression unit 10 to be driven by the linear motor 2 is mounted in the vehicle. However, the present invention is not limited to the case described above. For example, the compression unit 10 may be driven with use of a driving source other than the linear motor 2. Further, the compressor device of the present invention (for example, the linear motor compression machine 1) may be mounted in a machine or an apparatus other than the vehicle.

Further, in the embodiment, description has been made of the example case in which the compressor device (for example, the linear motor compression machine 1) is applied to a closed-type air suspension system in which the compressed air can be stored in the tank 36. However, the present invention is not limited to the above-mentioned case. The compressor device may be applied to, for example, an open-type air suspension system without using a storage tank for the compressed air (specifically, a system configured to exhaust the compressed air to the outside).

Further, in the embodiment, description has been made of the example case in which the linear motor 2, the compression unit 10, and the air dryer 23 are arranged in such a manner that center axis lines thereof match each other. However, the present invention is not limited to the above-mentioned case. The present invention does not preclude a case in which, for example, the linear motor, the compression unit, and the air dryer are arranged in such a manner that the center axis line of the compression unit and the center axis line of the air dryer are slightly offset with respect to the center axis line of the linear motor. Further, the center axis line of the linear motor and the center axis line of the air dryer may be offset with respect to the center axis line of the compression unit, or the center axis line of the linear motor and the center axis line of the compression unit may be offset with respect to the center axis line of the air dryer.

Next, for example, description is made of the following conceivable modes as the compressor device encompassed in the embodiment described above.

As a first mode of the compressor device, the compressor device includes a casing, an output shaft, a piston, a cylinder, and a cylinder head. A motor is housed in the casing. The output shaft projects from the casing, and is configured to be reciprocated by drive of the motor. The piston is provided to a projecting end of the output shaft. The piston is slidably provided inside the cylinder to form a compression chamber. The cylinder head is connected to the cylinder. A shielding portion configured to cover the cylinder in such a manner as to be separate from the cylinder in the radial direction of the cylinder is provided on an outer periphery side of the cylinder. The cylinder, the cylinder head, and the shielding portion are coupled to be integrated.

As a second mode of the compressor device, in the first mode, the cylinder and the shielding portion are connected to each other with a plurality of ribs. As a third mode of the compressor device, in the first or second mode, the compressor device includes an air dryer and solenoid valves. The air dryer is connected to the cylinder head, and is loaded with a desiccant. The solenoid valves are configured to control supply and exhaust of the compressed air to and from the air dryer. The solenoid valves are located on a radially outer side of the cylinder, and are fixed in a sandwiched state between the casing and the cylinder head. The shielding portion is provided on an outer side of the solenoid valves.

As a fourth mode of the compressor device, in any one of the first to third modes, a surface area of the shielding portion is larger than a surface area of the cylinder. As a fifth mode of the compressor device, in any one of the first to third modes, a surface area of the cylinder head is larger than a surface area of the cylinder. As a sixth mode of the compressor device, in the third mode, the shielding portion has opening portions formed so that the solenoid valves are exposed to an atmosphere.

Note that, the present invention is not limited to the embodiment described above, and includes further various modification examples. For example, in the embodiment described above, the configurations are described in detail in order to clearly describe the present invention, but the present invention is not necessarily limited to an embodiment that includes all the configurations that have been described. Further, a part of the configuration of a given embodiment can replace the configuration of another embodiment, and the configuration of another embodiment can also be added to the configuration of a given embodiment. Further, another configuration can be added to, deleted from, or replace a part of the configuration of each of the embodiments.

The present application claims a priority based on Japanese Patent Application No. 2018-178771 filed on Sep. 25, 2018. All disclosed contents including Specification, Scope of Claims, Drawings, and Abstract of Japanese Patent Application No. 2018-178771 filed on Sep. 25, 2018 are incorporated herein by reference in their entirety.

REFERENCE SIGNS LIST

1 linear motor compressor (compressor device), 2 linear motor, 3 casing, 4 armature (motor), 5 movable element (motor), 5A output shaft, 6 support member, 7 spring, 10 compression unit, 11 cylinder, 12 piston, 15 tubular shield (shielding portion), 15A tubular portion, 15B partition wall portion, 15C, 15D, 15E, 15F rib, 17 valve housing space, 20 cylinder head, 23 air dryer, 26 desiccant bead, 38 intake electromagnetic valve (solenoid valve), 40 return electromagnetic valve (solenoid valve), 41 supply/exhaust switching valve (solenoid valve), 44 exhaust electromagnetic valve (solenoid valve), 100 opening portion 

1. A compressor device, comprising: a casing in which a motor is housed; an output shaft, which projects from the casing, and is configured to be reciprocated by drive of the motor; a piston provided to a projecting end of the output shaft; a cylinder in which the piston is slidably provided to form a compression chamber; and a cylinder head connected to the cylinder, wherein a shielding portion configured to cover the cylinder in such a manner as to be separate from the cylinder in a radial direction of the cylinder is provided on an outer periphery side of the cylinder, wherein the cylinder, the cylinder head, and the shielding portion are coupled to be integrated, and wherein the cylinder and the shielding portion are connected to each other with a plurality of ribs.
 2. (canceled)
 3. The compressor device according to claim 1, further comprising: an air dryer, which is connected to the cylinder head, and is loaded with a desiccant; and solenoid valves configured to control supply and exhaust of a compressed air to and from the air dryer, wherein the solenoid valves are located on a radially outer side of the cylinder, and are fixed in a sandwiched state between the casing and the cylinder head, and wherein the shielding portion is provided on an outer side of the solenoid valves.
 4. The compressor device according to claim 1, wherein a surface area of the shielding portion is larger than a surface area of the cylinder.
 5. The compressor device according to claim 1, wherein a surface area of the cylinder head is larger than a surface area of the cylinder.
 6. The compressor device according to claim 3, wherein the shielding portion has opening portions formed so that the solenoid valves are exposed to an atmosphere.
 7. The compressor device according to claim 3, wherein a surface area of the shielding portion is larger than a surface area of the cylinder.
 8. The compressor device according to claim 3, wherein a surface area of the cylinder head is larger than a surface area of the cylinder.
 9. The compressor device according to claim 3, wherein a valve housing space is defined by the cylinder, the shielding portion and the ribs, and wherein a solenoid valve is disposed in the valve housing space. 